Uniform Channel Micro Heat Exchangers

Abstract

The performance characteristics of micro heat exchangers consisting of straight channels fabricated in a silicon wafer and operating with liquid nitrogen are evaluated theoretically. The three-dimensional conjugate temperature and flow fields are calculated numerically. The thermal resistance is computed as a function of various geometric parameters. The optimal dimensions which minimize the heat exchanger’s thermal resistance are identified. Additionally, a simple, approximate, analytical model, adequate when the ratio of the solid and liquid thermal conductivities is large, is presented and used to predict the heat exchanger’s optimal dimensions. The approximate model’s predictions are compared with the numerical results.